Neptuno was an 80-gun Neptuno-class ship of the line of the Spanish Navy. She was built in 1795 and took part in the French Revolutionary and Napoleonic Wars. She fought with the Franco-Spanish fleet in the battle of Trafalgar, and was wrecked in its aftermath.

The Battle of Trafalgar was a naval engagement that took place on 21 October 1805 between the British Royal Navy and the combined fleets of the French and Spanish Navies during the War of the Third Coalition of the Napoleonic Wars (1803–1815).